减压膜蒸馏法稀碱液浓缩过程研究

STUDY ON THE CONCENTRAT ION PROCESS OF Na_2S RAW PRODUCT SOLUTION BY VACUUM MEMBRANE DISTILLATION METHOD

以聚偏氟乙烯疏水膜为材料,采用减压膜蒸馏技术在较高真空度下浓缩硫化钠溶液,研究了各种条件对膜通量的影响。结果表明,当进料温度80℃、真空度为80 kPa、流速为0.99 m.s-1时,质量分数4.6%的硫化钠溶液VMD膜通量为23.7 kg.m-.2h-1;连续运行时,将稀碱液浓缩5倍后,膜通量仍维持在10.6 kg.m-2.h-1,用稀盐酸清洗后膜通量恢复到初始值的95.6%;浓缩过程产水电导维持在10μS.cm-1以下,脱盐率大于99.99%。

Hydrophobic polyvinylidene fluoride （PVDF） hollow fiber membrane was used in the concentration process of Na2S raw product solution, by vacuum membrane distillation （VMD） method. The effect of operation conditions of VMD process on the performance of the membrane was studied. The results showed that the flux increased as the temperature, velocity of the feed and the vacuum pressure increased. But the flux declined as the feed concentration enhanced. When tested at 80 ℃, with a feed velocity of 0.99 m·s^-1 and a vacuum pressure of 80 kPa, using the raw product from Nanfeng Chemical Plant （w=4.6%）, the flux reached 17.6 kg·m^-2·h^-1 and declined to 10.6 kg·m^-2·h^-1 as the final concentration reached 5 times of the original solution. After washing by HCl solution, a flux recovery rate of 95.6% was obtained.